Identify the correct statement.

• Lead forms compounds in +2 oxidation state due to inert pair effect.

• All halogens show only negative oxidation state.

• Catenation property increases from boron to oxygen.

• Oxadation state of oxygen is - 1 in ozonides.

An element has [Ar] 3d¹ configuration in its +2 oxidation state. Its position in the periodic table is

• period - 3, group - 3

• penod - 3, group - 7

• period - 4, group - 3

• period - 3, group - 9

Which of the following can be represented by the configuration [Kr] 5s²?

• Ca

• Sr

• Ba

• Ra

284.

Out of the following electronic configurations the one of a transition element, is

• 1s², 2s² 2p⁶, 3s² 3p⁶ 3d¹⁰, 4s² 4p⁶

• 1s², 2s² 2p⁶, 3s² 3p⁶ 3d³, 4s²

• 1s², 2s² 2p⁶, 3s² 3p⁶, 4s²

• 1s², 2s² 2p⁶, 3s² 3p⁶ 3d¹⁰, 4s² 4p¹

The element with atomic number 55 belongs to which block of the periodic table?

• s-block

• p-block

• d-block

• f-block

Which of the following has largest size?

• Al

• Al⁺

• Al²⁺

• Al³⁺

To which block is related an element having electronic configuration 1s², 2s² 2p⁶, 3s² 3p⁶ 3d¹⁰, 4s¹ in the periodic table?

• s-block

• p-block

• d-block

• f-block

The electronic configuration of an element is 1s², 2s², 2p⁶, 3s² 3p⁶, 3d¹⁰, 4s² 4p³. Its properties would be similar to which of the following elements?

• Boron

• Oxygen

• Nitrogen

• Chlorine

The number of unpaired electrons in Fe³⁺ (Z = 26 ) is

• 4

• 5

• 6

• 3

Outermost configuration for Z = 25, is

• 4s², 3d⁵

• 5s², 4d⁵

• 4s², 3d³

• 4s², 3d¹